While invasive rats are demonstrably inimical to indigenous vertebrate species, there has not been unequivocal evidence of benefit to invertebrate communities from management of these invasive mammals in New Zealand forest systems. The present study examined the response of land snail communities to intensive management of ship and Norway rats by sampling paired rainforest blocks, one block of which had been subject to intensive management of rats, while the other block had been without management of invasive rats and thus subject to ambient rodent infestations.
Anticoagulant poisons were laid within native forest at Wenderholm Regional Park (near Auckland) to reduce rat numbers during the summer months. Snap trapping indices and an artificial nest experiment confirmed the high potential for rat interference in unpoisoned forest patches outside Wenderholm, compared with the near-zero potential at Wenderholm. Over two breeding seasons, 70 New Zealand pigeon (Hemiphaga novaeseelandiae) nests were located and monitored.